Re: Linux i/o tweaking

Joel Jaeggli
2001-11-15T18:18:27Z

I guess the question I'd ask would be what kinda number do you expect from
the raid 5 stripe. 107MB/s sounds like a reasonable number from a two
channel u160 controller...

my previous best is around 89MB/s with 4 cheetah 15K 18gb drives raid/0

On Thu, 15 Nov 2001, Roy Sigurd Karlsbakk
wrote:

> Hi all
>
> After three days at Compaq's lab in Oslo, testing their medium-level
> servers and storage systems with Linux, I've come to some sort of
> conclusions, although these may be wrong. I also have come over a few
> problems that I couln't find a good solution to.
>
> * When running RAID from a Compaq Smart 5302/64 controller, software
> RAID-5 is (slightly - ~15%) faster (on JBOD - each disk is configured as
> a RAID-0 device with max - 256kB - stripe size) than the
> hardware/controller based RAID-5. Both CPUs (1266MHz/512kB cache) are
> maxed out by reading from software RAID-5 (???), giving me >= 107MB/s on
> two SCSI-3 buses with six disks on each bus.
>
> * Even though I can get up to 25 MB/s from each disk, I can't get more
> than 107 MB/s on the whole bunch (12 drives). It doesn't help much to do
> RAID-0 either. Don't understand anything ...
>
> Thanks for all help.
>
> roy
>
> --
> Roy Sigurd Karlsbakk, MCSE, MCNE, CLS, LCA
>
> Computers are like air conditioners.
> They stop working when you open Windows.
>
>
>
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Joel Jaeggli joelja@darkwing.uoregon.edu
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